[ARC5] Radios in XB-19?

Mon Jan 11 17:05:03 EST 2016

Ah Ha!  Makes some sense.  Apparently the term was brought forward into the
solid state era as well.  Why not...

Next time I'll look it up - search engines are my friend...What a concept!

Thanks Bart - see you at the next Gala....!
Tim

On Mon, Jan 11, 2016 at 1:34 PM, Bart Lee <kv6lee at gmail.com> wrote:

> That's an interesting question and I didn't know what the answer was.  So
> I went to the Wiki:
>
>  Given the right auxiliary and control equipment, an M-G set or rotary
> converter can be "run backwards", converting DC to AC. Hence an inverter is
> an inverted converter.[11]
> <https://en.wikipedia.org/wiki/Power_inverter#cite_note-11>
>
>    1.  Owen, Edward L. (January–February 1996). "Origins of the
>    Inverter". *IEEE Industry Applications Magazine: History Department*
>     (IEEE) *2* (1): 64–66.
>
>
> I like the Wiki so much, at least for technical questions, that I send
> them money every year.
>
> 73
>
> de Bart, K6VK ##
>
>
> -- --
> Bart Lee,
> Attorney at Law
> Office Phone 415 956 5959 x203
> Office Fax Line 415 362 1431
> Cell Phone 415 902 7168
> Snail Mail: 388 Market St #900
> San Francisco, CA 94111-5311
> www.bartlee.com
> <http://www.LawForHams.com>
>
>
> On Mon, Jan 11, 2016 at 12:46 PM, Jay Coward via ARC5 <
> arc5 at mailman.qth.net> wrote:
>
>> You are inverting the DC back and forth?
>> Jay
>>
>>
>> -----Original Message-----
>> From: Tim <timsamm at gmail.com>
>> To: Michael Hanz <aaf-radio-1 at aafradio.org>
>> Cc: To: ARC-5 <arc5 at mailman.qth.net>; Military Surplus Mail List (
>> milsurplus at mailman.qth.net) <milsurplus at mailman.qth.net>
>> Sent: Mon, Jan 11, 2016 10:57 am
>> Subject: Re: [ARC5] Radios in XB-19?
>>
>> Hi Smart Guys!  Question:  Why are DC-to-AC devices called "inverters"
>> ??  Seems like an odd choice for a name...What am I missing?
>>
>> Tim
>> N6CC
>>
>> On Mon, Jan 11, 2016 at 5:47 AM, Michael Hanz <aaf-radio-1 at aafradio.org>
>> wrote:
>>
>>> I think it more likely that Douglas and the Army had studied Navy
>>> practice, which included mounting an 800Hz alternator on one engine, and
>>> decided to try having both AC *and* DC available as a development
>>> platform.  The Navy was pretty much ahead on everything related to
>>> avionics, and by the late 1930s had recognized that new devices like radar,
>>> HF transmitters like the GO-9 and GP-7, and devices requiring small amounts
>>> of AC power, such as navigation equipment and the like, were going to need
>>> both kinds of power.  However, in their haste to implement a native AC and
>>> DC environment on their combat aircraft, the Navy missed the mark with
>>> 800Hz, because the higher frequency needed compensating capacitors
>>> installed that could be adjusted for a particular load to eliminate the
>>> effect of inductive reactance in the alternator.  As it turned out, 400Hz
>>> was a better compromise between eliminating that need and still reducing
>>> the size and weight of transformers in airborne equipment.  That's how we
>>> ended up with the current standard for aircraft.
>>>
>>> That being said, the Army was slow to follow the Navy's lead, preferring
>>> to keep the primary mode of power to DC, and distributing small DC to AC
>>> inverters to where they were needed in a point of presence approach.
>>> That's how they accommodated new pieces of equipment in all the heavies,
>>> including the B-29.  A DC bus was never far away throughout the airframe,
>>> and tapping into it was easier and weighed less than trying to run two
>>> separate busses throughout the plane during manufacture.  You can see a
>>> couple of these (by 1945) ubiquitous MG-149 alternators at the navigator's
>>> station in the Enola Gay -
>>> http://aafradio.org/NASM/Enola_cockpit_026a.jpg - though larger
>>> alternators were required by power hogs like the APQ-13 radar.
>>>
>>> The Navy did the same thing (to an extent) with their 800-1 alternator (
>>> http://aafradio.org/docs/800-1.htm ), (again, fighting the inevitable
>>> evolution to 400Hz), but those appear to have been used for the same reason
>>> that the Army did - to serve unexpected pieces of equipment being
>>> retrofitted to aircraft after they came off the assembly lines.  It wasn't
>>> until after the war when technology settled down enough to think about
>>> providing both kinds of power throughout any given airframe.
>>>
>>> 73,
>>> Mike  KC4TOS
>>>
>>> On 1/10/2016 11:23 PM, Bart Lee wrote:
>>>
>>> I heard that 400 cycle power was implemented in the B-29 because
>>> otherwise the weight of the transformers would have been too much to fly
>>> well.  (Incidentally, my father was a B-29 Flight Engineer).  Maybe the
>>> XB-19 prototyped 400 cycle AC power.
>>>
>>> 73 de Bart, K6VK
>>>
>>> On Sun, Jan 10, 2016 at 4:44 PM, Jay Coward via ARC5 <
>>> arc5 at mailman.qth.net> wrote:
>>>
>>>> Well Jack and the Group,
>>>>  I've always wondered what radio equipment was in the Bolo.
>>>>  As far as AC in the XB-19 , it may have been the power distribution
>>>> system and the AC to DC was done locally at the equipment. Just guessing as
>>>> there is not much AC gear surfacing from that era.
>>>> Jay KE6PPF
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Jack Antonio <scr287 at att.net>
>>>> To: milsurplus <milsurplus at mailman.qth.net>; ARC-5 List <
>>>> arc5 at mailman.qth.net>
>>>> Sent: Sun, Jan 10, 2016 9:59 am
>>>> Subject: [ARC5] Radios in XB-19?
>>>>
>>>> Does anyone have any documentation on the radios installed
>>>> in the Douglas XB-19?
>>>>
>>>> Note, this not a typo, I am not referring to the B-18 Bolo.
>>>>
>>>> The XB-19 was the large experimental bomber that was used more
>>>> as a test bed for large aircraft systems, rather than a serious
>>>> contender for production.
>>>>
>>>> What drives the question, is that one of the features of the plane
>>>> was the use of an AC power system.
>>>>
>>>> So I'm wondering if the Army used AC powered radios in the plane.
>>>>
>>>
>>>
>>> ______________________________________________________________
>>> ARC5 mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/arc5
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:ARC5 at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>>
>> ______________________________________________________________
>> ARC5 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/arc5
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:ARC5 at mailman.qth.net <ARC5 at mailman.qth.net?>
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>> ______________________________________________________________
>> ARC5 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/arc5
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:ARC5 at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20160111/19bfdc8c/attachment.html>